lost pla casting

Discussion in 'Home Foundry & Casting Projects' started by aonemarine, Jul 1, 2013.

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  1. Jul 1, 2013 #1

    aonemarine

    aonemarine

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    Well I decided to try my hand at the lost pla casting. PLA is a plastic that is used for printing on 3d printers. Imagine designing something in your cad program, printing it, then investment casting it into a metal part :eek:
    This run didnt come out that well but I did learn a few new tricks, and I know the next run will come out 100 times better.
    [ame]http://www.youtube.com/watch?v=GgZvtrNI7iM[/ame]
     
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  2. Jul 1, 2013 #2

    Putt-Rite

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    Now that looks interesting.
     
  3. Jul 1, 2013 #3

    Lakc

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    Did you bake out the PLA like lost wax or displace it like lost foam?
     
  4. Jul 1, 2013 #4

    aonemarine

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    It was baked out in the kiln all day up to 730C, I needed to burn it out for a few more hours there was still some stuff in the molds that left inclusions in the castings. This was a good learning experience.
     
  5. Jul 1, 2013 #5

    aonemarine

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    heres a pic of the iron part, the surface finish isnt that great but im certain that if the right investment is used it will come out much much better...

    steamchestiniron 002.jpg
     
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  6. Jul 1, 2013 #6

    LSEW

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    aone, very interesting.

    Thinking about it, why not print a mold of the part and pour in wax, then make your investment mold from the wax?

    Also, what kind of plaster did you use? I have been interested in investment casting with bronze for a while now, but haven't jumped in yet.

    Just did a bronze/petrobond pour today.

    maury
    www.lonestarengineworks.com
     
  7. Jul 1, 2013 #7

    aonemarine

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    Maury, thats in the works as well. The one part is a mold (printed in abs) for wax injection. I need to get a few things worked out but I feel there is real potential here. The investment was Americast from Ranson and Randolph. I plan on ordering some Kerr Platinite for the next iron cast. Here is a couple pics of the printed wax molds and the casting. Not 100% yet but the next pour will be better.

    IMAG0993.jpg

    printedsolidmold.jpg
     
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  8. Jul 1, 2013 #8

    aonemarine

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    On a side note, abs printed core boxes could save alot of time for sand cast items ;)
     
  9. Jul 1, 2013 #9

    jwcnc1911

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    aonemarine,

    man you have almost convinced me to take up casting. if i could squeeze 30 more seconds in a day i would make time to do it. It looks like your retaining wall really helps with your work. would you recommend having a stone table or something to replace the retaining wall. sort of a casting work bench?

    excluding the 3d printing and mould making, from the moment you decided to make the pour, how long did it take? i mean the actual pour. from getting your already made moulds together, putting on your gear, so on so on. is one pour basically a day project or can you knock it out in a few hours?
     
  10. Jul 1, 2013 #10

    Herbiev

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    Great effort. As they say " practice makes perfect" and it looks like you're well on the way
     
  11. Jul 1, 2013 #11

    aonemarine

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    JW, the total length of the casting session was 45 minutes. That's from first lighting, melting aluminum, then switching crucibles and melting iron. The investment process was maybe an hours worth of work. That involved spreuing up the parts, mixing the investment, vaccuming the investment, and pouring the investment. Once the investment is poured you let it sit from a few hours th a couple days, then start the burn out.
    My kiln is fitted with a digital temp controller so its a matter of program it and let it go.
    Now if I'm sand casting, depending on the part to be molded, I can ram up a mold in 15 minutes or less and poured in less than an hour.
    I got dreeves hooked on casting, it only took him one casting session to get the bug and start building himself a furnace. And melting aluminum can be done in a metal cylinder in a good campfire. You can make your own green sand from some cheap fine sand and ground up kitty litter.
    So what's stopping you??
     
  12. Jul 2, 2013 #12

    jwcnc1911

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    Fear of the unkown man! Just kidding... I still lack knowledge to get started and I think good wife might kill me if I take on one more project that requires time.

    I see you wearing PPE and you have all of these nice tongs you're lifting crucibles with and I'm sure many other goodies I'm not aware of.

    Programmed temp control... did you do this with a purchased unit or did you do something like an arduino setup?

    I've been studying... I figure I'll make the plunge in the Fall and into Winter.
     
  13. Jul 2, 2013 #13

    moya034

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    The only way to really learn casting is to start making mistakes and figuring out how to correct them.
     
  14. Jul 2, 2013 #14

    Lakc

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    Thats true about everything. With casting, you have to keep your mistakes in the sand, and not make harmful ones, or ones injurious to life or limb.
     
  15. Jul 2, 2013 #15

    aonemarine

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    PPE is important, casting in flip flops bad. ;)

    Gloves and face sheld are a must and thats all I used until I started casting bronze then iron, thats when the danger level went up 100 fold.
    I have been casting for about 5 years now, and so far have avoided getting burnt, but there is all ways that one time.
    At the end of the video there is a screen shot of molten iron flying over my shoulder, I didnt see it while I was casting but Moya did and told me at the end of the casting session. It was interesting to see it on video, I never saw it when it happened....
     
  16. Jul 2, 2013 #16

    jwcnc1911

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    aonemarine,

    In the video, the first glowing hot item you set on the ground... is that a heated mould? The moulds are heated to glowing hot as well?
     
  17. Jul 2, 2013 #17

    aonemarine

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    They were that hot, but honestly they should have only been about 200C.
    Being as hot as they were caused some shrinkage issues in the castings where the sprue cooled faster than the part (in the center of the mold) and robbed metal from the casting. I also needed to extend the burn out time as there was still some residue inside the mold that caused inclusions in the castings and I also noticed some steam tracking on the cast parts (also an indicator of too short a burn out time) It was a learning experience for sure. Now I have a much better idea of what to do so the next castings will be well improved.
    If I can perfect this process....man the sky is the limit!!
     
  18. Jul 2, 2013 #18

    jwcnc1911

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    The sky is the limit if you have a HUGE 3d printer! Did you DIY your 3d printer? I've been considering that too (I like your style all the way around it seems!).
     
  19. Jul 2, 2013 #19

    aonemarine

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    No, the printed parts are from a friends 3d printer, he has actually started a small printing business (printedsolid.com) and has some interesting things he has printed on his web site. I am really surprised at the quality of prints you can get now from what they were a couple of years ago.
    I may diy my own printer and have been sitting parts off to the side, but to be honest the cost of the printers has come down so much it might be better off just to buy one.
     
  20. Jul 2, 2013 #20

    jwcnc1911

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    I agree, I've been watching these for about 5 years now. We got one at work and I saw it printing "prototypes" but they were coarse, "boxy" and very rough. It seems the resolution of the extrusion is much better nowadays.

    You can get a Cubify for about $1k if you call them and talk them down.

    A bit of a horror or goth fellow?
     

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